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Green Roof Rules and Regulations

Thursday, August 30, 2012

Hurricane season is upon us. Importantly, Florida Green Roofs should have adequate design consideration provided for keeping plants on the roof during storm events.

One of my favorite design tools is use of three dimensional geo synthetic fabrics to allow a plant's root architecture to form a strong bond between plant and roofing system.

The above video shows a green roof panel containing a three dimensional weave and soil media along with some organic compost. The panel is being pressure washed to remove the soil media.

As the video shows, the green roof soil media is not easily removed. Three dimensional weaving provides excellent wind and water resistance and can be very helpful for sloped green roof stabilization or any green roof subject to extreme weather conditions.

Monday, August 27, 2012

Recently, one of the original field trial green roofs was temporarily removed to allow for installation of a solar hot water system piping. The roof's slope was approximately 7/12 and originally the lightweight extensive mat system was installed over the existing asphalt shingles (with a root barrier/waterproofing liner). The green roof system used a soil media comprised of primary organic mixtures, had a variety of sedum, succulents and native Allium species planted (A. canadense and others).

Florida Green Roof, MetroVerde Extensive Mat System

The sedum and original Aptenia struggled over time, eventually giving way to the A. canadense, primarily due to fungal attacks during the steamy hot, humid summer months (not necessarily rainy just high water vapor months).

Once removed the underlying roof appeared to look the same as the day the green roof was installed seven years ago, free of water damage and quite nicely preserved.

The green roof system was a simple.ost-effective system defying all odds and wagging-tongues - (don't use high organic soil media, the roof is too sloped, can't put a green roof over asphalt shingles, a nature-irrigated green roof will not survive, etc...). The system easily survived several tropical cyclones, one rainfall event where we had eighteen inches of water in over two days (Tropical Storm Fay), extended periods of brutal drought and more). The roof never had additional soil or plants added to it.

Once the solar piping was in place the intent was to add a recycled section of old, heavy duty chain link fence to the wall under the roof and plant and grow luffa gourds in the gutter, allowing them to cascade down over the guter edge across the chain link living wall fencing. I can hear the wagging tongues now - growing plants in gutter!

Florida Green Roof, Luffa Gourds in Gutters

Importantly, over the years of watching the roof preform the plants adsorbed and drank most of the rainfall events - especially any rain less than one inch (most of our afternoon rainstorms here are les than one inch) rendering the gutter useless. The gutter was useless in the eighteen inch plus rainfall event too. Though I would not do this on a commercial application, we do push the limits at the nursery to see what systems can do. I am confident the green roof system we've replaced on the roof will handle any and all precipitation events, even with the luffa planted in the gutter, and just as the organic matter did not clog and wash out or decompose as predicted or the roof wash off during tropical cyclones, the luffa planted gutter - filled with a fast draining soil media will pleasantly surprise us.

The luffa is deciduous and will allow winter sun to hit our masonry walls, adding heat in the cooler months yet shading out summer solar radiation.

So with skyrocketing food prices in the grocery markets, a food based schema was designed for plantings. The original mat, removed during the solar renovation process was replaced, adhered using a low VOC roofing glue.

Florida Extensive Green MetroVerde Green Roof, Mat installed

Once the mat was in place and inspected the soil media was added. This is the process where the greatest leap of faith occurs for me.

Florida MetroVerde Extensive Green Roof Soil Media

A leap of faith because placing soil on a quite steep roof surface seems to be a futile approach, one probably washing off during the first rain storm, covering outside walls with a muddy mess. Of course we watch the weather predictions as would any roofer and don't start if rain is predicted for a couple days.

The soil media is a fine material, free of aggregate - important when designing in a cyclone prone area. Our soil media specifications call for microscopic sharp, geometric edges capable of locking together and when roots are added to the blend a highly stable, well-drained monolithic system is created. The trick lies in initially adding fast growing C3 plants to bind all together then incorporating a purposeful evolution to a blend of more C4 and CAM plants to allow for drought tolerance and wind resilience.

Florida Extensive Green Roof, Matt's Wild Cherry Tomatoes

Since I love Wild Cherry Tomatoes and cannot get enough of them I decided on Matt's Wild Cherry Tomatoes to accompany the luffa's. This wild breed produces more delicious cherry tomatoes than any other variety I have seen. I am expecting thousands and thousands of cherry tomatoes this year.

Florida Green Roof, Food Roof, Rooftop Permaculture by MetroVerde

Cherry tomatoes are ramblers and will cascade down alongside the luffas, down the living wall so I won't have to actually climb the roof to fetch the round red scrumptious fruits.

Florida Green Roof - Rooftop Permaculture

Expect update photos as the luffa's and tomatoes grow and fill in the living wall, cascading down from above, providing us and countless hungry insects, birds and other Urban Jax Core wildlife with fresh organic nectar, food and beauty.

Watch out for patterns on a green roof. The randomness of natural plant habitat is far more interesting to the subconscious than pretty and unnatural geometric patterns.Having walked and waded through Florida's swamps most of my life, I've had to always watch for alligators, poisonous snakes and biting insect nests. Swamp trekking involves slow tedious movements, especially if the water you are walking through is dark and you cannot see what you are stepping on. Logs, holes and other obstacles often times lie just under the surface making a fast get-away nearly improbable.

Importantly most of the potentially dangerous animals in a swamp are non-aggressive unless bothered. An alligator typically (I say typically because there have been known aggressive and fatal attacks) won't bother you unless it feels threatened. Same way with rattlesnakes and stinging insects.

A water moccasin is a mean creature and just as often as not they will chase you. Pushing my way through three meter tall saw palmetto along the edge of a creek one day I had a large water moccasin, Agkistrodon piscivorus, jump out of a saw palmetto, Serenoa repens, and begin striking at my legs. In my attempt to retreat I tripped and fell into the water where the snake continued to pursue after me and left with the choice of dispatch with my machete or have the moccasin bite me between the legs I cut the reptiles head off swiftly. Unfortunately, the snake's aggressiveness is embedded rather strongly within its DNA and the severed head continued to jump and strike for most of a minute, quite frighteningly.

I say all of this to make a point about biodiversity and green roofs.

One of the many things I've learned from the swamps is a subconscious awareness of patterns. When I am in the field where dangerous animals are located I look for patterns. In the plant community there are few large geometric community patterns other than the flower. But on the ground plant habitat is always random in visual nature. However, when my eye catches a glimpse of a solid geometric pattern in length, width or height I immediately look to see what type of animal I am approaching.

Plant communities will always exhibit more randomness in their visual patterns than animals. This is true even when walking through a seemingly uniform pine flatwoods area covered in meadowbeauty or wire-grass. The habitat may seem uniform yet there is the randomness of spacing between the pines and between the plants.

Recognizing patterns has saved me from stepping on a still lying 'gator' many times.

And the random beauty of plant communities, the lines, curves, colors and hues is nature's way unique way of fingerprinting - everything is unique. There are no exact and identical plant formations in nature.

Complicated uniqueness is the focal point of bio-diversity. Each plant system or wildlife community is diverse in biological constituency, hence the tern 'bio' - 'diversity'.

A nature-focused, native species green roof should be designed accordingly.

The subtle inundation's and changing ground elevation lines should be reflected on the roof. Green roof soil media gradations of 10 mm to 50 mm across a relatively flat stretch of roof are important. Elevation changes in living roof soil media provide much more than visual interest - they serve as wind breaks, assist in the collection, transport and storage of rainwater, dew and fog and provide shelter for visiting wildlife.

Too many times we may simply rake a green roof sol media flat. Allowing slight fluctuations in the soil media mimics nature and ultimately may allow for more chances at green roof community planting successes.

The same holds true for species mixes on green roofs. The general rule for a nature-based biodiverse planting is the 10-20-30 rule. The 10-20-30 rule guides us to plant no more than 10% of the green roof with any one Species, 20% of the roof with one Genera and 30% of the roof with one Family.

Monoculture plantings on green roofs are confusing to wildlife and provide sub-standard communal and foraging habitat.

And while it may be easy to call out in design the one or two proven plants for a green roof project, the long term habitat value will be diminished with a green roof that only contains one type of plant. Remember, even if the design intent is to have a solid, one color and one texture appearance across the roof, this can be accomplished with using a mix of similar appearing species. One does not have to create monocultures on green roofs to achieve design intent!

Friday, August 17, 2012

The green roof over Breaking Ground Contracting has been the subject of many posts here, primarily because every time I have the opportunity to take photos of the living roof the plants there are expressing themselves with new and unique bio-patterns.

Florida Extensive Green Roof in Jacksonville, Florida

The roof is a Florida extensive living roof, designed for tropical storm and hurricane resiliency.The plants are a blend of native wildflowers, grasses, succulents, herbs and more.After enduring early summer droughts and two tropical storms, the roof is full of pollinators and looks magnificent.Breaking Ground Contracting's living roof serves to cool Urban Heat Island effects, provides wildlife habitat, attenuates and cleans stormwater, sequesters carbon, pumps out oxygen, provides beauty in the Urban Concrete Jungle and more.

Thursday, August 16, 2012

Composting can provide many benefits for Floridans. Composting recycles nutrients sequestered by plants back into fertilizer-like substances. Plants then utilize composted organic matter to grow.

Composting though, must take place in the right place and right manner. Open raw compost may create serious health issues.

When we design Urban Green systems, including stormwater shelves and bioswales, we try to specify plants that contribute a minimum of leaf litter to the waterways. Deciduous plants, even if they are native species or important food plants may contribute too much biomass in the form of leaf drop (litter). Though there is a time and place for nitrogen and phosphorous rich compost, the excess biomass may not belong in community ditches, open lots or out in the open. Instead, proper composting may require proven permaculture approaches.

Though we desperately need to create urban habitat for wildlife, we must also create habitat in a responsbile manner. Whereas food chain effects and predators control nuisance wildlife populations such as rodents, squirrels and raccoons, these critters can cause serious health and safety issues in the Urban Core if attracted by improperly treated compost. Racoons in particular are significant carriers of roundworms and other parasites. Very recently, someone we knew well was hospitalized at Shands in Gainesville for life-threatening roundworm issues attributed to racoons around their house. Epidemiology studies show racoons to be a serious health issue in some locals and carry parasitic creature eggs that can infiltrate even the cleanest of houses on the bottom of sandals or shoes.

Properly composted organic matter may potentially be used in a safe manner in Florida permaculture gardens, yet as with all fertilizers, compost should be used in a specific application, one directed at food or landscape garden growing. Keeping nutrients where they are needed and out of Florida's water systems is an important and oft-overlooked component of good permaculture science.

By keeping additional nutrient rich organic and composted plant matter out of the aquifer, our creeksand rivers and other waterbodies we also limit potential for suffocating algal growth.

Algae, like any other plant relies on nitrogen and phosphorous to grow. The more nitrogen and phosphorous in water, the more algae in the waterbody.

While there is nothing inherently wrong with algae, like any other living organism uncontrolled algal growth can choke out all other forms of life, stealing all available oxygen from the water and blocking light neccessary for photosynthesis.

Keeping nutrients out of the water that may feed algae is an important reason for keeping compost and dead and decaying plants out of aquatic systems. Simply put, nutrients sequestered out of the water by being taken up through plants should not be allowed to reenter waterways. Once a plant dies and decomposes, most previously sequestered nutrients may be released from the plant matter back into the water. Once back in the water column nutrients feed more algae blooms with potent nitrogen and phosphorous compounds.

The above photo depicts giant bullrush growing in a stormwater facility, taking up and sequestering toxins and nutrients.

Practically speaking, herbicide use in ponds to control weeds never really promotes clean water. In fact once plants die from herbicide application the once sequestered nitrogen and phosphorous leach out of the dead plant material back into the water. What was once removed from the water column is soon released back into the aquatic environment. These nutrients can travel for hundreds of miles dissolved in underground aquifer water to reemerge in a pristine river or lake. Soon algae may be filling our our waterbodies, including those used for recreation and water supply.

Same pond as above, one month later after herbicide application, bullrush composting into the pond, rereleasing toxins and nutrients back into the aquatic system

The above photo depicts giant bullrush sprayed with herbicide, now composting in the pond, soon to release previously sequestered nutrients and toxins back into the water supply.

Though many municipalities today use herbicide applications to keep algae and other plants at bay, the process is self-defeating. As soon as the sprayed algae and aquatic plants such as cattail and reed die and compost where they once grew, all the nitrogen and phosphorous originally sequestered becomes rereleased into the aquatic ecology to fuel more algal growth.

A better solution for removing nutrients and toxins from stormwater facilities is to harvest the plant biomass after cuttinginstead of spraying with herbicide. Removing sequestered nutrients this way is refered to 'nutrients in -nutrients out'. Nutrients and toxins flow into the ponds, plants grab and sequester the nutrients, plants are harvested thus removing nutrients from the waterway systems.

Composting can be a good permaculture practice if done where nuisance wildlife are not attracted into residential areas and thenutrients are not rereleased back into our waterways.

Spraying herbicides to kill algae and other vegetation in ditches and stormwater ponds is composting in an incorrect manner.

Using native evergreen plants and those plants with low leaf litter rates can reduce the necessity to remove vegetation litter and algae.

Harvesting the biomass and composting in a well designed municipal or neighborhood facility can keep nutrients out of Florida's waterways and our waterbodies free from unneccessary algal blooms.

Biomass translates into carbon sequestration, oxygen production and mitigation of Urban Heat Island Effect.Native wildflowers such as Mimosa, Phyla, Rudbeckia, Gaillardia and Bidens are blooming. Herbs such as lemongrass, mint, rosemary and thyme are growing well.

Green Roof Benefits are Many and Include Stormwater Attenuation, Urban heat Island Mitigation and more!

Native grasses too, compliment the plantings, along the native Yucca filamentosa.Urban greening is so important for many reasons. Kudos to the Tappouni sisters, Mary, Michelle and Catherine for their efforts in making Jacksonville a greener place to live, work and play!

Ligustrum vulgare, Visual Screen for Site Infrastructure. Though Ligustrum japonicum, Common Privet is not a native plant, she is a drought tolerant landscape species offering much more benefit to the Urban Core than fencing panels.

Here, once again Publix has shown visionary design approaches by specifying plants for infrastructure screens. Ligustrum or Common Privet, Ligustrum japonicum is not a native plant species however it is considered to be a drought tolerant and reliable landscape plant.

Even more encouraging was the fact that the reviewing county agency approved the use of plants for a visual screen rather than wooden panels or galvanized chain link.

Kudos to the designers and to the permitting staff for allowing and even encouraging Urban Greening.

Hopefully we will see more native plant landscapes serve as site design elements in the Urban Core.

Here is an interesting photo of a Florida extensive green roof - 2-4" thick on a 5/12 slope (built in 2005) with a HDPE root barrier. A portion of the vegetated roof has been removed for root barrier inspection and root behavioral studies. The plants are growing in a soil filled woven mat and the roots are thick into the mat. Once the roots reach the liner they turn and grow parallel with the liner's surface.

Florida is subject to summer tropical storms and hurricanes. Wind speeds of over one hundred miles per hour are typically seen across rooftop systems during these weather events.Three dimensional mats serve multiple purposes in green roof systems.First, the mat holds soil media in place on both flat and sloped roofs.Second, the mat allows for green roof and living wall plant roots to anchor to a permanently attached roofing component, reducing the potential for blow-off during wind events.There are many materials a mat may be fabricated from, both natural and synthetic substances.Consider a growing mat on your next green roof or living wall project.

Friday, August 10, 2012

With two tropical depressions in the Atlantic and several cyclonical systems developing this August 2012 hurricane season, the October 2010 video of green roof hurricane tests in UF's Civil Engineering facility is reposted along with the original narrative.As food becomes scarcer and more Urban Ag activities spring up across our cities, material science will play an important role in designing secure plant growing systems for patios, walls and roofs.Though the video is quite long, Urban Green roof and hurricane design issues require comprehensive attention to potential safety issues, just as any other roofing material or system would demand.October 2010:We started off today referring to the Green Roof Wind Uplift Test duration as "until failure".At least it looked as though the test would proceed until the mat failed.After all, the MetroVerde Green Roof had been sitting in the hot Florida sun, non-irrigated, 1" thick layer of engineered soil for 18 months at the University of Florida.We are going into our fifth week of zero precipitation (no rain).The plants looked brown.The panel was fixed at a 3/12 slope just feet away from the large hurricane simulator.The plants appeared vulnerable, the engineered soil just waiting to be blown off the mat along with vegetation.The large diesel engines fired up and the turbines spun.50 MPH for one minute - dust blew off the roof.70 MPH for a minute plus - not much happened except the plants whipped back and forth.90 MPH and the dust around the base of the testing platform flew and the plants bent backwards - almost parallel to the roof slope. Shingles on a shed 300' away began flapping.We were all amazed, having seen other green roofs under hurricane tests blow away, soil and plants...We took a break and looked at the panel. A small amount of the engineered soil had blown off the mat.The 120 MPH for over three minutes.The dead, brown material blew off the plants - like a good pruning. Even the large, tender Echeveria was still there, albeit leaning a little.The nodding garlic - Allium canadense was beautiful.The plant roots were so intertwined in the mat that 80% of the engineered soil remained.Successful. The first Florida Designed Green Roof Panel to pass the 120 MPH wind uplift test.

Lots learned -

Will be working with UF more in the future!

Enjoy the video - I'll post the link as soon as YouTube finishes processing it - in the meantime here are a couple pics and happy Green Roofing!

These photos from May of 2011 illustrate how Urban Green can be established to create habitat corridors through out the Urban Core. Native plants, Florida Friendly species, vegetables, grasses and more live on the rooftop garden.

The Tappouni sisters' efforts with 'greening Jacksonville' are part of an important sustainability web being woven by the next generation.

"Here are some photos of the Breaking Ground Contracting food and wildflower green roof in Jacksonville. Even though we've had a terrible drought, the green roof plants have grown very nicely. This roof is irrigated with rain water and uses only HVAC condensate. Right plant, right place with CAM species on the perimeter and C4 species inside the CAM belt. Model your design for wind and sunlight! Enjoy the photos!. 10-20-30 rule met so far! We have approximately 150 plants species and counting!"

The front bed is filled with Yucca filamentosa, one of Florida's native yuccas and a great habitat provider for wildlife.

Importantly, the BGC office incorporates volumetric green from the street to the roof. Native grasses extend from the edge of the roadside right-of-way to the front door, around the building and up to the rooftop.

These photos were taken my Mary Tappouni who owns Breaking Ground Contracting (I borrowed them from Twitter for this post). The Florida green tree frog is a Hyla cinerea. H. cinerea is under predator pressure from the larger, more agressive and invasive Cuban Tree Frog. However the native plants across BGC's site provide refuge for the smaller native tree frog.

Soon after the BGC green roof was installed, H. cinerea appeared on the rooftop vegetation. I suspect several eggs came in on native plants.

Though small and almost unnoticeable, H. cinerea is a voracious eater and can consume a great amount of otherwise pest bugs such as mosquitos and roaches.

Creating habitat for native wildlife is an important facet of Urban Greening. Year after year, the Breaking Ground Contracting office's landscape is successfully providing foraging and communal refuge for Florida's native wildlife.